1. Field of Invention
The present invention relates to apparatus for preventing infection from unsterile hypodermic needles or the like, and more particularly to a system for preventing needle stick or re-use of unsterile hypodermic needles or like items.
The present invention teaches in its preferred embodiment a hypodermic syringe wherein there is included a spring biased, locking push button apparatus exterior to the syringe plunger which communicates with a locking safety sheath situated at the base of the hypodermic needle prior to activation.
The safety sheath is in sliding, longitudinal communication about the needle, and is activated to its sheathing position by urging a push button on the locking push button structure in the direction of the needle, directing the sheath from about the base of the needle to over the tip of the needle. Upon communication with the tip, the safety sheath deploys a locking hatch, preventing the urging of the sheath back to the base, and rendering the needle thereafter un-reusable.
The locking apparatus of the present invention preferably operates independently of the syringe plunger, allowing the drawing and injection of fluids without interference, and is sheathed in locking position only upon the independent urging of the push button, "clicking" the sheath into a locked position.
2. Prior Art and General Background
While the prior art may teach a plurality of various devices configured to protect against needle sticks, none teach or contemplate the system as contemplated in the present invention, wherein there is provided redundant locking as a "fail-safe" apparatus.
Since the early 1980's it has been recognized that instruments which come into contact with human tissue fluids can comprise biohazards, particularly when those instruments come into contact with HIV, hepatitis, and other tissue infected with contagion.
Further, it has been recognized that the sharing and re-usage of disposable needles has transmitted HIV among intravenous drug users.
Consequently, there has evolved a plethora of re-designs of existing hypodermic syringes and related devices, wherein there has been incorporated features to prevent infection and, in the case of disposable systems, reuse.
Often, the distraction surrounding a medical emergency or like situation may result in used syringes not being identified as being particularly contaminated. This could result in the re-use of the syringe by a medical professional and potential contamination resulting therefrom.
Additionally, if the syringe is not properly disposed of, an addict may thereafter utilize it to administer illegal drugs to himself and others, spreading the virus, bacteria, disease, or anything else which may be present on the point and shaft of the hollow metal needle.
It is for this reason that an easily operated, consistent and tamper proof, syringe needle capping system is needed, so that the utilized needle may be automatically capped immediately after use, even in the heat of a medical emergency, without distraction and in a consistent and unfailing manner.
A list of prior patents which may be of interest is presented below:
______________________________________ Patent No. Patentee(s) Issue Date ______________________________________ 4,702,738 4,725,267 Vaillancourt 02/16/88 4,790,828 Dombrowski et al 12/13/88 4,804,371 Vaillancourt 02/14/89 4,813,940 Parry 03/21/89 4,838,863 Allard et al 06/13/89 4,846,796 Carrell et al 07/11/89 4,850,968 Romano 07/25/89 4,861,338 Mathiesen et al 08/29/89 4,863,434 Bayless 09/05/89 4,887,998 Martin et al 12/19/89 4,894,055 Sudnak 01/16/90 4,908,023 Yuen 03/13/90 4,921,486 DeChellis et al 05/01/90 4,932,940 Walker et al 06/12/90 4,936,830 Verlier 06/26/90 4,955,868 Klein 09/11/90 4,966,593 Lennox 10/30/90 4,986,818 4,994,046 5,026,353 Bartman 06/25/91 ______________________________________
U.S. Pat. No. 4,702,738 addresses the problem of inadvertent pricks, but the safety is easily manipulated once the system is locked by manipulating the spring force, easily overcoming it by hand. Further, the difficulties in performing the basic functions of using the syringe are increased by the need for holding the shield handle during injection.
U.S. Pat. No. 4,725,267 addresses the problem of inadvertent pricks by covering the point of the needle, but activating it requires the operator to work in the area of the point of the needle, increasing the potential contamination risk simply to cover the needle. Further, the cover could be forced back, exposing the needle, potentially causing a prick.
U.S. Pat. No. 4,790,828, issued in 1988, teaches a "Self-capping Needle Assembly", wherein in FIGS. 1, 2 and 6, there is contemplated a locking needle capping assembly utilizing biased blockage means, albeit distinguishable in operation and design from that contemplated by the present invention. Namely, the activation system which must be manually lifted in the '828 system is more cumbersome to operate with one hand and could actually encourage needle stick, versus the present invention, which contemplates a push-button system wherein there is a lesser chance for needle stick during the activation of the capping mechanism.
U.S. Pat. No. 4,804,371 addresses the problem of inadvertent pricks by covering the needle, but can be pushed out of the way if one desires to overcome the system, thereby failing to prevent re-use.
U.S. Pat. No. 4,994,046, issued in 1991, discloses a "Needle Guard for Syringe", wherein there is taught a side mounted apparatus for controlling the shield means, albeit completely distinguishable in form and operation from the present invention.
U.S. Pat. No. 4,863,434, issued in 1989 describes an "automatic needle sheath for disposable syringe" wherein a needle capping assembly is disclosed (note FIG. "A"), offering biased blocking members to cover the needle. However, the '434 patent fails to contemplate an efficient, inexpensive, and safe system as taught in the present invention.
U.S. Pat. No. 4,936,830 addresses the problem of inadvertent pricks and reuse, but works only on pre-filled syringes.
U.S. Pat. No. 4,986,818, issued Jan. 22, 1991, and U.S. Pat. No. 4,990,141, issued Feb. 5, 1991, also teach single use syringes utilizing a type of safety capping assembly again distinguishable from the present invention, but nonetheless pertinent with respect to the generalized concept of a single use syringe system.
Finally, U.S. Pat. No. 5,026,353 issued Jun. 25, 1991 teaches a "multi-chamber safety syringe", contemplating a rather bulky, complicated, and expensive system for preventing needle stick, wherein there is taught essentially the incorporation of dual spring biased reciprocating pistons on opposing sides of the syringe to force forward a capping assembly.
As taught, the device of the '353 patent may not only be considered impractical, but also does not teach a safe locking mechanism over the needle. In fact, as the capping system is apparently contemplated, the cap is not locked in place over the needle and may in fact slide out of the needle cap, if the cap is urged towards the base of the needle, exposing it. Therefore, if one were to bump or sit atop the cap, the cap could slide back, sticking and potentially infecting that person.
3. General, Summary Discussion of the Invention
Although the prior discussed patents disclose a plethora of various needle capping systems, none teach or contemplate the reliable, inexpensive, and easily operated system of the present invention.
As may be discerned by a review of the above, one can understand why so few systems for preventing needle stick have been commercially successful in the marketplace.
Literally dozens of various apparatus configurations have been presented to prevent needle stick or syringe re-use, but all have their flaws, particularly with regard to ease of use, reliability, safety and cost.
The present system not only provides all of the above, but does so in a system which is less complicated than most of those contemplated in the prior art.
Unlike the prior art, the present invention provides a simple system for implementing a needle cap after use which is redundant, providing locking with regard to the needle cap once in the capping position, as well as a locking system in the initiating mechanism. This is done in an easy, push-button system designed to be literally fool proof and tamper proof.
The present invention contemplates in its preferred embodiment a plunger-type syringe and needle arrangement, with a side mounted, initiating mechanism in longitudinal communication with a capping or protective cover mechanism. Both the capping mechanism and protective cover incorporate oblique locking means for maintaining the system permanently in a locked, unsliding position once the locking push button has been initiated.
In the initiation mechanism, there is provided a spring biased push button and shaft arrangement, wherein the shaft moves longitudinally along its enveloping sleeve until it activates a one-way locking mechanism, while simultaneously biasing the protective cap along the needle until it covers the tip of the needle.
Once the needle tip has been covered, the one-way locking mechanism in both the initiation mechanism and protective cover engage, preventing any subsequent needle stick or re-use.
It is therefore an object of the present invention to provide a system for preventing needle stick which incorporates redundant protective cover locking means.
It is another object of the present invention to provide a system for preventing needle stick wherein there is included a side mounted, push-button initiation system incorporating a longitudinal migrating shaft and enveloping sheath for urging a protective cap along a needle, covering it.
It is another object of the present invention to provide a system for preventing needle stick, wherein there is implemented a protective sheath or cover for the needle which permanently locks in place once it slides over the tip of the needle.
Lastly, it is an object of the present invention to provide a system for preventing needle stick or the like, which is inexpensive, reliable, and safe to implement and utilize.